Method and device for producing a formed part

ABSTRACT

The invention relates to a method and a device for producing a shaped part from a circular blank, wherein the circular blank is rotated and at least one compression roller is radially applied to an outer edge of the circular blank, said compression roller having a circumferential shaping groove. The outer edge of the circular blank is compressed to form a thickened region, which is shaped according to the shaping groove of the compression roller to form a thickened edge contour. With the radial compression, at least two axial shaped rollers are applied to an outer region of the circular blank, which cooperate when shaping the edge contour. According to the invention, at least in a starting phase of the radial compression, the two axial shaped rollers are applied to the thickened region at an axial shaping distance to one another, which distance is smaller than an axial width of the shaping groove of the compression roller, wherein the thickened region is axially compressed back.

The invention relates to a method for producing a formed part from a circular blank, in which the circular blank is set into rotation and at least one upsetting roller, which has a circumferential forming groove, is fed radially to an outer edge of the circular blank, the outer edge of the circular blank is upset to a thickened region which is formed to a thickened edge contour according to the forming groove of the upsetting roller, and during radial upsetting at least two axial forming rollers, which cooperate during the forming of the edge contour, are applied or fed laterally to an outer region of the circular blank, in accordance with the preamble of claim 1.

The invention further relates to a device for producing a formed part from a circular blank with a drive means for driving a circular blank in a rotating manner and with at least one upsetting roller which can be fed radially to the circular blank in order to upset the outer edge of the circular blank, in accordance with the preamble of claim 9.

It is known that a circular blank, i.e. a rotationally symmetrical workpiece of sheet metal, is upset by radially feeding an upsetting roller with a circumferential upsetting or forming groove in order to create a material accumulation. Into the material accumulation e.g. a toothing, for creating a gear wheel or a starter rim gear, can then be formed in a chipless manner or cut in a chip-removing process.

Due to the radial feeding of the upsetting roller considerable radial forces are exerted onto the circular blank. To prevent the edge of the circular blank from bending during upsetting it is known from DE 102 11 135 B4 that the circular blank is supported directly below the upsetting region by lateral supporting rollers.

Furthermore, from DE 196 02 298 C2 it is known that the lateral supporting rollers are used as a kind of lateral counter-bearing which contributes to the radial forming of the edge bead of the circular blank. In this, the forming rollers can also form a radially internal lower edge of the edge contour.

During the radial upsetting of a circular blank edge by means of an upsetting roller with circumferential forming groove considerable loads occur on the upsetting roller. As soon as the groove base of the forming groove makes contact with the outer edge of the circular blank, the radial feeding of the upsetting roller initially causes material of the circular blank to be displaced axially towards both sides. With an increasing radial feeding, the displaced material is then led along the flanks of the upsetting roller in the radial inward direction and thickened further, whereby the diameter of the circular blank is gradually reduced. In doing so, considerable friction occurs along the flanks of the forming groove due to the different movement between circular blank and upsetting roller in the circumferential direction. This can result in a correspondingly strong frictional heat-up which may affect the structure of the workpiece.

To reduce loads it is known from WO 96/22847 A1 or from U.S. Pat. No. 5,878,493 A that upsetting is carried out step by step with several different upsetting rollers that have different flank angles in the forming grooves. The use of a plurality of different upsetting rollers is costly and time-consuming.

Similar methods for upsetting a circular blank of sheet metal using an upsetting roller can be taken from DE 196 35 152 A1 and from EP 0 764 482 A1.

The invention is based on the object to provide a method and a device, with which a formed part of a circular blank can be processed in a particularly efficient manner whilst the edge of the circular blank is being thickened.

The object is achieved by a method having the feature of claim 1 and by a device having the features of claim 9. Preferred embodiments of the invention are stated in the respective dependent claims.

The method according to the invention is characterized in that at least in a starting phase of radial upsetting the two axial forming rollers are fed to the thickened region with an axial forming distance to each other which is smaller than an axial width of the forming groove of the upsetting roller, wherein the thickened region is back-upset axially.

A basic idea of the invention resides in the fact that at least in a starting phase of the radial upsetting of a circular blank the at least one upsetting roller is relieved in that the lateral flanks of the thickened region are directly acted upon by two axial forming rollers. The axial distance of the two opposite forming rollers is set such that at least in some regions it is smaller than an axial width of the forming groove of the upsetting roller. Thus, through the two axial forming rollers the thickened region, after having left the forming groove of the upsetting roller, is back-upset axially to a thickness that is smaller than a width of the forming groove. Due to this back-upsetting of the thickened region in the axial direction the contact surface and thus the friction between the flanks of the forming groove and the flanks of the thickened region is reduced when the back-upset region re-enters the upsetting roller. Accordingly, this reduces the load of the upsetting roller, frictional wear as well as the frictional heat-up in the forming zone. As a result, an altogether more gentle forming can be achieved both for the structure of the workpiece and for the upsetting roller itself.

According to a further development of the invention a particularly good reduction of friction can be accomplished in that the at least two axial forming rollers are applied or fed directly behind and/or before the upsetting roller. The forming rollers arranged in pairs can be arranged just a few cm behind or before the upsetting roller.

Another advantageous embodiment of the invention resides in the fact that the two axial forming rollers are adjusted axially to each other during upsetting. The axial forming rollers each have an axis of rotation that is directed radially to the axis of rotation of the circular blank. The axial distance of the two axial forming rollers to each other is a length that is preferably parallel to the axis of rotation of the circular blank. The axes of rotation of the axial forming rollers can also be angled with respect to the radial direction, thereby also allowing a back-upsetting on inclined flanks of the thickened edge region of the circular blank. Through axial adjustment of the forming rollers to each other the contact surface between circular blank and forming rollers can be set, in which case the friction changes accordingly. Especially at the end of radial upsetting an axial distance of the axial forming rollers to each other can be enlarged so that a finish-forming is substantially effected by the forming groove of the upsetting roller. The forming rollers can have radially protruding shoulders which serve as an abutment or stop ridge to form e.g. a radial inner side or underside of the edge contour.

Moreover, according to an embodiment variant of the method pursuant to the invention it is advantageous for the two axial forming rollers to be adjusted radially during upsetting. Through this, in particular an adaptation to a gradual reduction of the circular blank diameter during upsetting can be effected.

For a precise forming of the thickened edge contour it is advantageous in accordance with an embodiment variant of the invention that in a final phase of radial upsetting the axial forming rollers are spaced from the thickened region and the thickened region is finish-formed to the edge contour by the at least one upsetting roller. For this, the forming groove in the upsetting roller is designed according to the edge contour of the circular blank that is to be created.

According to a further development of the invention a particularly efficient method variant resides in the fact that in the same clamping of the circular blank an outer edge with the formed-on thickened edge contour is folded over onto a spinning tool and a circumferential wall region is formed. The circular blank is clamped between the spinning tool and a counter-holder. In a first step an edge thickening is carried out, and subsequently, in the same clamping, the thickened region of the circular blank is folded over onto the spinning chuck. Through this, a cylindrical or cup-shaped workpiece can be produced in a chipless manner with an internal contour that preferably corresponds to the external contour of the spinning tool.

In this connection, it is particularly advantageous for the folding-over to be carried out by means of at least one upsetting roller. The upsetting roller has a multiple function. Due to this multifunctional upsetting roller the number of spinning rollers required and tools can be reduced.

For an efficient forming in accordance with a method variant pursuant to the invention it is advantageous that during folding-over the thickened edge contour is formed into an external profiling, in particular a splined groove profile or a toothing, which is designed on the spinning chuck. On the circumferential wall a corresponding internal profile is designed. Basically, other profiles and contours can also be formed.

A possible upsetting roller is characterized in that a radially protruding spinning region is additionally provided that is designed for spinning and/or for flow-forming.

The upsetting roller can thus assume a double function. It serves for the radial upsetting with a radial application of force and for folding over the radial edge region of the circular blank axially onto the spinning chuck, in which case substantially axial forces are being applied. Hence, the upsetting roller is designed with a rotary bearing which absorbs both radial and axial forces.

A preferred embodiment variant of the upsetting roller resides in the fact that the upsetting region is arranged in an axial center section and the spinning region in a lateral edge section of the roller body. The spinning region is radially protruding and has a spinning radius.

According to an embodiment variant it is especially advantageous that in cross-section the spinning region has a radially protruding nose with a spinning radius and a run-in and/or run-out slope. The run-in slope can in particular be designed such that a folding-over of the radially directed circular blank section is effected through an axial movement of the upsetting roller.

The device according to the invention for producing a formed part from a circular blank is characterized in that an upsetting roller is provided.

According to an embodiment of the invention it is particularly preferred that for the clamping of the circular blank a spinning chuck is provided, on which an external profiling is designed, onto which an edge section of the circular blank can be folded over to create a formed part with internal profiling. The spinning chuck is part of a clamping means, with the circular blank being clamped axially between spinning chuck and a counter-holder. Due to the previous thickening a sufficient amount of material is available to reliably fill the external profiling.

The invention is described further hereinafter by way of preferred embodiments illustrated schematically in the accompanying drawings, wherein show:

FIG. 1 a partial cross-sectional view of a device according to the invention at the beginning of a radial upsetting of a circular blank;

FIG. 2 an illustration according to FIG. 1 at the end of the radial upsetting of the circular blank;

FIG. 3 a partial cross-sectional view of the circular blank before upsetting;

FIG. 4 a partial cross-sectional view of the circular blank after upsetting;

FIG. 5 a schematic side view of the device according to the invention corresponding to FIG. 2;

FIG. 6 a partial cross-sectional view of the device according to the invention during folding-over of a circular blank edge onto a profiled spinning chuck; and

FIG. 7 a partial cross-sectional view corresponding to FIG. 6 during finish-forming of a formed part.

According to FIG. 1, in a device 10 pursuant to the invention for producing a formed part a rotationally symmetrical circular blank 1 of sheet material is clamped axially by being centered between a spinning chuck 12 and a counter-holder 20. By way of a non-depicted rotary drive the clamped circular blank 1 is set into rotation.

From the radial outward direction an upsetting roller 50 with a roller base body 52 is fed to an outer edge of the circular blank 1. On the roller base body 52 in a central section thereof an upsetting region 54 with a circumferential forming groove 56 is designed. The outer edge of the circular blank 1 is received in the forming groove 56 which predetermines an external contour of the circular blank region to be upset.

The roller base body 52 is mounted on an upsetting roller shaft 74 which is rotatably supported via a radial bearing 76 and an axial bearing arrangement 78 in a holder 80. The support by means of radial bearing 76 and axial bearing 78 renders it possible to absorb forming forces both in the radial direction and in the axial direction.

Radially opposite the upsetting roller 50 a first axial forming roller 41 and a second axial forming roller 42 are provided which are applied on the opposite side axially to the circular blank 1 to be formed. In the forming region the first axial forming roller 41 and the second axial forming roller 42 have an axial forming distance that is smaller than an axial width of the forming groove 56 of the upsetting roller 50. The two forming rollers 41, 42 are each mounted on a roller shaft 43 which are rotatably supported in a first roller support 45 and a second roller support 46 respectively. The first roller support 45 and the second roller support 46 are supported in an adjustable manner on a guide carrier 48. Adjustment can be carried out via a non-depicted adjustment means, more particularly a positioning cylinder or a spindle drive.

By radially feeding the upsetting roller 50 to the rotating circular blank 1 the outer edge of the circular blank 1 is upset. In doing so, the upset material initially accumulates on a groove base 59 and then on flanks 58 of the forming groove 56. In contrast to the groove base 59 the flanks 58 of the forming roller 50 and the accumulated material of the circular blank 1 have a different direction of movement. To reduce friction the two axial forming rollers 41, 42 are fed axially to the thickening circular blank edge, whereby a certain axial back-upsetting, e.g. amounting to approximately 10% of the wall thickness, of the thickened region of the circular blank 1 takes place. Through this, a frictional contact is at least reduced when the thickened region re-renters the upsetting roller 50. As a result, frictional wear, a structure-damaging frictional heat-up and a load of the upsetting roller 50 are reduced considerably.

At the end of forming the thickened edge contour 3 of the circular blank 1 the axial forming rollers 41, 42 can be spaced further at least to an axial distance that corresponds to the width of the forming groove 56 so that the thickened edge contour 3 on the circular blank 1 is principally formed by the contour of the forming groove 56 of the upsetting roller 50.

FIGS. 3 and 4 illustrate that during radial upsetting an external diameter of the circular blank 1 is reduced, and at the same time a thickened edge contour 3 is created along the outer edge.

A final phase of forming the thickened edge contour 3 with the upsetting roller 50 and the two axial forming rollers 41, 42 is shown schematically in FIG. 5. It can also be taken from FIG. 5 that on an outer side of the spinning chuck 12 an external profiling 14 is provided. In the illustrated embodiment the external profiling 14 is realized as an axial splined groove profile.

By means of one or several upsetting rollers 50 the outer edge of the circular blank 1 with the thickened edge contour 3 can be folded over axially onto the external profiling 14 of the spinning chuck 12, as illustrated schematically in FIG. 6. For this purpose, the upsetting roller 50 according to the invention is provided with an edge-sided spinning region 60 in addition to the central upsetting region 54 with the forming groove 56. In the spinning region 60 a radially protruding nose 62 with a spinning radius is provided which merges on the one hand into a run-in slope 64 and on the other hand into a run-out slope 66. Furthermore, the upsetting roller 50 according to the invention can also have an opposite frontal spinning region 70, with which a front side of the workpiece to be formed can be processed. Alternatively or additionally, for folding-over a further flow-forming roller 30 can be fed to the circumference of the workpiece.

In the depicted embodiment according to the illustration of FIG. 7, for the finish-forming of the formed part 9 a frontal profile 16 can finally be formed. To this end, the upsetting roller 50 can be fed with a frontal spinning region 70 to a front side of the formed part 9. In the frontal spinning region 70 the upsetting roller 50, depicted schematically only, has a protruding spinning ridge of approximately rectangular shape.

On completion of the final forming step the formed part 9 is ejected and removed from the spinning chuck 12 by means of a displaceable, annular ejecting means 90. The formed part 9 can be a clutch plate carrier for automatic transmission. Subsequently, for the forming of a further workpiece a new circular blank 1 can be fed to the device 10 and clamped between the spinning chuck 12 and the counter-holder 20. 

1. A method for producing a formed part from a circular blank, in which the circular blank is set into rotation and at least one upsetting roller, which has a circumferential forming groove, is fed radially to an outer edge of the circular blank, the outer edge of the circular blank is upset to a thickened region which is formed to a thickened edge contour according to the forming groove of the upsetting roller, and during radial upsetting at least two axial forming rollers, which cooperate during the forming of the opposite edge contour, are applied or fed laterally to an outer region of the circular blank, wherein at least in a starting phase of radial upsetting the two axial forming rollers are fed to the thickened region with an axial forming distance to each other which is smaller than an axial width of the forming groove of the upsetting roller, wherein the thickened region is back-upset axially.
 2. The method according to claim 1, wherein the at least two axial forming rollers are applied or fed directly behind and/or before the upsetting roller.
 3. The method according to claim 1, wherein the two axial forming rollers are adjusted axially to each other during upsetting.
 4. The method according to claim 1, wherein the two axial forming rollers are adjusted radially during upsetting.
 5. The method according to claim 1, wherein in a final phase of radial upsetting the axial forming rollers are spaced from the thickened region and the thickened region is finish-formed to the edge contour by the at least one upsetting roller.
 6. The method according to claim 1, wherein in the same clamping of the circular blank an outer edge with the formed-on thickened edge contour is folded over onto a spinning chuck and a circumferential wall region is formed.
 7. The method according to claim 6, wherein the folding-over is carried out by means of the at least one upsetting roller.
 8. The method according to claim 6, wherein during folding-over the thickened edge contour is formed into an external profiling, in particular a splined groove profile or a toothing, which is designed on the spinning chuck.
 9. A device for producing a formed part from a circular blank pursuant to the method according to claim 1, with a drive means for driving a circular blank in a rotating manner and with at least one upsetting roller having a forming groove, which can be fed radially to the circular blank in order to upset the outer edge of the circular blank to a thickened region, and with at least two axial forming rollers which can be fed laterally to the circular blank wherein for the clamping of the circular blank a spinning chuck is provided, on which an external profiling is designed, onto which an edge section of the circular blank can be folded over to create a formed part with internal profiling, wherein the external profiling is a splined groove profile or a toothing, in that during radial feeding and upsetting by means of the at least one upsetting roller the two axial forming rollers are fed to the thickened region of the circular blank with an axial forming distance to each other which is smaller than an axial width of the forming groove of the upsetting roller, and in that on the upsetting roller a spinning region with a radially protruding nose having a spinning radius and a run-in slope and a run-out slope is provided for folding over the radially directed circular blank section of the circular blank through an axial movement.
 10. (canceled) 